Safety brakes are known per se and rely on releasing a previously prepared mechanism which serves, either directly or indirectly, to move one or more friction bodies towards each other should the moving member exceed a reference value (speed or length of stroke). Several types of actuator mechanism are known, and they may include a spring mechanism which is latched in a state of accumulated energy, or else a counterweight mechanism which is held in a "high" position. At least some such latching or holding means include a hydraulic circuit generating a pressure which opposes the release of the energy accumulated by the brake members actuator mechanism. The pressure in this circuit is lost or reduced in response to an emergency stop signal generated by a sensor, e.g. a sensor for sensing excess speed or position of the moving member. These prior systems suffer from the drawback of using electrical or electronic sensors which are relatively fragile and which therefore require considerable care and maintenance.
The invention seeks to provide a safety brake of much simpler construction and with much simpler maintenance requirements, and suitable for being implemented in conjunction with numerous moving members.